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   PID: hpt/lnx 1.9.0-cur 2019-01-08   
   TID: hpt/lnx 1.9.0-cur 2019-01-08   
    Human embryo-like models created from stem cells to understand earliest   
   stages of human development    
      
     Date:   
         June 27, 2023   
     Source:   
         University of Cambridge   
     Summary:   
         Scientists have created a stem cell-derived model of the   
         human embryo in the lab by reprogramming human stem cells. The   
         breakthrough could help research into genetic disorders and in   
         understanding why and how pregnancies fail.   
      
      
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   FULL STORY   
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   Cambridge scientists have created a stem cell-derived model of the human   
   embryo in the lab by reprogramming human stem cells. The breakthrough   
   could help research into genetic disorders and in understanding why and   
   how pregnancies fail.   
      
   Published today in the journal Nature, this embryo model is an organised   
   three- dimensional structure derived from pluripotent stem cells that   
   replicate some developmental processes that occur in early human embryos.   
      
   Use of such models allows experimental modelling of embryonic development   
   during the second week of pregnancy. They can help researchers gain   
   basic knowledge of the developmental origins of organs and specialised   
   cells such as sperm and eggs, and facilitate understanding of early   
   pregnancy loss.   
      
   "Our human embryo-like model, created entirely from human stem cells,   
   gives us access to the developing structure at a stage that is normally   
   hidden from us due to the implantation of the tiny embryo into the   
   mother's womb," said Professor Magdalena Zernicka-Goetz in the University   
   of Cambridge's Department of Physiology, Development and Neuroscience,   
   who led the work.   
      
   She added: "This exciting development allows us to manipulate genes to   
   understand their developmental roles in a model system. This will let   
   us test the function of specific factors, which is difficult to do in   
   the natural embryo."  In natural human development, the second week   
   of development is an important time when the embryo implants into the   
   uterus. This is the time when many pregnancies are lost.   
      
   The new advance enables scientists to peer into the mysterious 'black   
   box' period of human development -- usually following implantation   
   of the embryo in the uterus -- to observe processes never directly   
   observed before.   
      
   Understanding these early developmental processes holds the potential   
   to reveal some of the causes of human birth defects and diseases, and   
   to develop tests for these in pregnant women.   
      
   Until now, the processes could only be observed in animal models, using   
   cells from zebrafish and mice, for example.   
      
   Legal restrictions in the UK currently prevent the culture of natural   
   human embryos in the lab beyond day 14 of development: this time limit was   
   set to correspond to the stage where the embryo can no longer form a twin.   
      
   Until now, scientists have only been able to study this period of human   
   development using donated human embryos. This advance could reduce the   
   need for donated human embryos in research.   
      
   Zernicka-Goetz says the while these models can mimic aspects of the   
   development of human embryos, they cannot and will not develop to the   
   equivalent of postnatal stage humans.   
      
   Over the past decade, Zernicka-Goetz's group in Cambridge has been   
   studying the earliest stages of pregnancy, in order to understand why   
   some pregnancies fail and some succeed.   
      
   In 2021 and then in 2022 her team announced in Developmental Cell, Nature   
   and Cell Stem Cell journals that they had finally created model embryos   
   from mouse stem cells that can develop to form a brain-like structure,   
   a beating heart, and the foundations of all other organs of the body.   
      
   The new models derived from human stem cells do not have a brain or   
   beating heart, but they include cells that would typically go on to form   
   the embryo, placenta and yolk sac, and develop to form the precursors   
   of germ cells (that will form sperm and eggs).   
      
   Many pregnancies fail at the point when these three types of cells   
   orchestrate implantation into the uterus begin to send mechanical and   
   chemical signals to each other, which tell the embryo how to develop   
   properly.   
      
   There are clear regulations governing stem cell-based models of   
   human embryos and all researchers doing embryo modelling work must   
   first be approved by ethics committees. Journals require proof   
   of this ethics review before they accept scientific papers for   
   publication. Zernicka-Goetz's laboratory holds these approvals.   
      
   "It is against the law and FDA regulations to transfer any embryo-like   
   models into a woman for reproductive aims. These are highly manipulated   
   human cells and their attempted reproductive use would be extremely   
   dangerous," said Dr Insoo Hyun, Director of the Center for Life Sciences   
   and Public Learning at Boston's Museum of Science and a member of Harvard   
   Medical School's Center for Bioethics.   
      
   Zernicka-Goetz also holds position at the California Institute of   
   Technology and is NOMIS Distinguished Scientist and Scholar Awardee.   
      
   The research was funded by the Wellcome Trust and Open Philanthropy.   
      
       * RELATED_TOPICS   
             o Health_&_Medicine   
                   # Pregnancy_and_Childbirth # Stem_Cells # Birth_Defects   
                   # Human_Biology # Lymphoma # Medical_Topics #   
                   Prostate_Cancer # Skin_Cancer   
       * RELATED_TERMS   
             o Embryonic_stem_cell o Stem_cell o Adult_stem_cell   
             o Stem_cell_treatments o Somatic_cell o   
             Somatic_cell_nuclear_transfer o Gene_therapy o   
             Bone_marrow_transplant   
      
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   Story Source: Materials provided by University_of_Cambridge. The original   
   text of this story is licensed under a Creative_Commons_License. Note:   
   Content may be edited for style and length.   
      
      
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   Journal Reference:   
      1. Bailey A. T. Weatherbee, Carlos W. Gantner, Lisa K. Iwamoto-Stohl,   
      Riza   
         M. Daza, Nobuhiko Hamazaki, Jay Shendure, Magdalena   
         Zernicka-Goetz. A model of the post-implantation human embryo   
         derived from pluripotent stem cells. Nature, 2023; DOI:   
         10.1038/s41586-023-06368-y   
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   Link to news story:   
   https://www.sciencedaily.com/releases/2023/06/230627123010.htm   
      
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